Thread-cutting device for circular knitting machines



July 16, 1968 FQNTAINE 3,392,550

THREAD-CUTTING DEVICE FOR CIRCULAR KNITTING MACHINES Filed Jan. 26, 1967 4 Sheets-Sheet 1 0| c 1 I 1' a o c/ I n@ o o "r l INVENTOR. L. For? fad ne.

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4 Sheets-Sheet 4/ L. FONTAINE July 16, 1968 THREAD-CUTTING DEVICE FOR CIRCULAR KNITTING MACHINES Filed Jan. 26, 1967 EigfZ INVENTOR. L. ontcu'ne BY GLLJMJdL ATTORN EBS July 1 968 FONTAINE THREADCUTTINQ DEVICE FOR CIRCULAR KNITTING MACHINES Filed Jan. 2 1967 L Fo n t Q ATTCHL 55 y 1968 I FONTAINE 3,392,550

THREAD-CUTTING DEVICE FOR CIRCULAR KNITTING MACHINES Filed Jan. 26, 1967. 4 Sheets-Sheet 4 INVENTOR.

L. F on t a 6n 6.

ATT o I'LN E55 United States Patent 7 Claims. (e1. 66-140) ABSTRACT OF THE DISCLOSURE The danger of burning threads in a circular knitting machine is avoided by a thread-cutting device operable to move the heating wire under the underside of a notched disc when the thread is being changed and withdrawing the heating wire after the thread is severed.

This invention relates to an improved thread-cutting device for multi-feed circular knitting machines of the type comprising a notched disc disposed at a level adjacent to the upper level reached by the needles in their vertical rising movement, said disc cooperating with the thread guides to bring the inactive threads towards the center of the knitting crown.

In such machines, it has already been proposed to provide said notched disc with a thread-cutting device consisting substantially of a heating wire passing through an orifice therefor in the disc and near the center thereof, the heating wire extending beyond the underside of the disc. The latter is carried by an axis the upper end of which is held by a bracket leaning on an annular holder linked to a stationary portion of the machine and the lower end of which has a section of smaller diameter passing through said disc and bearing a cap forming a screen under said heating wire.

Although it is very simple and effective, this known thread-cutter has nevertheless the drawback of burning accidentally the knitwear. This is most often observed when starting knitting a cylindrical article since the already formed stitch courses which are not sufficiently numerous to be subjected to the full effects of the knitwear suction or traction device, have a tendency to come in the horizontal plane near the underside of said disc, i.e .to contact the heating wire.

An object of the present invention is to prevent this drawback. This invention relates to a thread-cutting device of the type consisting of a heating wire passing through an orifice provided therefor near the center of said disc and extending beyond the underside of the latter, characterized in that it comprises means bringing the heating wire into operating position under the underside of the notched disc when changing a thread during the knitting operation and bringing back the heating wire into inactive position after severing a thread brought at rest position.

According to another characteristic of the invention, the heating wire is only supplied when it is brought into active position.

In this way, any danger of burning the knitwear is substantially avoided, the heating wire being only brought to incandescence at due time and during a relatively short time period. Thus, the temperature of the relatively confined space defined between the underside of the notched disc and the elaborated knitwear will never reach a critical value for the knitwear, which was not the case in the above known device.

The characteristics and the advantages of the invention will be more apparent from the following detailed ice description of two embodiments of the invention with reference to the enclosed drawing in which:

FIGURE 1 is a perspective diagrammatic view of the knitting head of a four feed knitting machine provided with the device according to the invention;

FIGURE 2 is a diagrammatic axial section of the knitting head represented in FIGURE 1, showing the thread guide device and the thread-cutter according to the invention;

FIGURE 3 is a section on the line III-III of FIG- URE 2;

FIGURE 4 is a plan view according to the arrow P4 of FIGURE 2;

FIGURE 5 is a diagrammatic section according to the line VV of FIGURE 2;

FIGURE 6 is a view similar to that of FIGURE 3 representing another embodiment of the thread-cutting device according to the invention and FIGURE 7 is a section similar to that of FIGURE 5 of the device represented in FIGURE 6.

The knitting head represented by way of example in FIGURE 1 comprises a needle carrying cylinder 1 surrounded by a mantle 2 provided with a lower dial 3 and an upper dial 4 as well as thread guide rocking levers 5 pivoting about a common axis 6, said axis being supported by two strands 7-8 leaning upon an annular support or lid 9 pivoting about an axis 10.

This annular lid 9 has a circular opening 11 within which is disposed a notched disc 12 coaxial with the needle cylinder I. Said disc 12 is carried by a tubular element 13 supported by a bracket 14 which is itself secured through screws 15 on the annular rim of the said lid 9.

The disc 12 comprises four narrow notches respectively 16, 17, 18 and 19 opening each in an eyelet respectively 20, 21, 22 and 23, said notches being inclined relative to the periphery of the disc 12 and oriented opposite to the normal rotation direction of the needle cylinder 1. Adjacent to each of the notches 16 to 19 and on the upperside of the disc 12 is disposed a spring steel blade respectively 24, 25, 26 and 27. Each of said blades has, at one end, an eyelet through which passes a screw 28 securing said blade, the other end of the latter being bent upwards as represented in 29.

Near its center, the disc 12 is provided with an oblong orifice 30 for passing a substantially U-shaped heating wire 31 each leg of which is connected via screws 32 and 33 with a lead under rigid sheath respectively 34 and 35. These leads 34 and 35 are secured through tightening nuts represented in 36 to a small insulating plate 37 which is in turn secured to the armature 38 of an electro-plunger 39 being secured through screws 40 to the horizontal leg of a stirrup 41 both legs of which are secured through screws 42 to the bracket 14.

The armature 38 has a generally cylindrical shape provided, near its median portion, with a shoulder 43, the lower end 44 of said armature 38 engaging with an easy fit a tubular element 45 engaging itself said tubular member 13. The element 45 is made integral with the lower end 44 of the armature 38 through a screw 46. The lower end of the tubular element 45 receives a cap 47 having a truncated recess 48 facing the underside of disc 12.

The shoulder 43 has a double tfunction, namely limiting, in low position, the downwards movement of the tubular element 45 and, in high position, actuating a microswitch 49 carried by the said stirrup 41.

The device operates as follows: during the knitting operation, the electro-plunger 39 is energized, thereby bringing the tubular element 45 into high position, thereby withdrawing the heating wire 31 from the underside of said disc 12 and applying the peripheral edge of cap 48 3 I thereagainst. In this high position, shoulder 48 actuates themicroswitch 49, thereby breaking the supply of the heating wire 31. When changing the thread, the device programming the machine breaks up the energizing of the electro-plunger 39, thereby bringing the heating wire 31 into active position under the underside of disc 12 and supplying said heating wire '31 by releasing microswitch The embodiment represented in FIGURES 6 and 7 uses the same constructionprinciples as those of the above described example, so that the same references are used for indicating similar elements. In this embodiment, the small plate 37 supporting the leads 34 and 35 as well as the heating wire 31 is secured through a screw 50, to the upper end of a rod 51 engaging the tubular member 13 of the device 12, the lower end of said rod 51 carrying the cap 47. The small plate 37 has a side finger 52 extending above and parallel to bracket 14, the latter having a stud 53 coaxial to a corresponding stud 54pmvided on the underside of the said finger 52, thereby centering and holding a helical spring 55 repelling finger 52 upwards, i.e. tending to bring the peripheral edge of cap 47 against the underside of disc 12. the heating wire 31 is brought into active position under the action of the electro-plunger 39 the armature of which 38 acts upon the end of a lever 56 pivoting about an axis 57 journalled in a support 58 integral with bracket 14, the other end of said lever 56 acting upon said finger 52. This device operates in the same manner as the preceding embodiment with reference to FIGURES 1 to 5.

It is understood that the above examples are given only by way of illustration since, without departing from the scope of the invention, numerous modifications may be provided as well to the shape as to the relative arrangement of the constituting elements of a thread-cutting device according to the invention.

What I claim is:

1. In a circular knitting machine having a needle cylinder and needles, a thread-cutting device comprising a notched disc, a heating wire passing through an orifice provided therefor near the center of said disc and extending beyond the underside of the latter, said notched disc being coaxial with said needle cylinder, and means bringing the said heating wire into operating position under the underside of said notched disc when changing a thread during the knitting operation and bringing back the said heating wire into inactive position after severing a thread brought at rest position.

2. Thread-cutting device according to claim 1, having means supplying electric current to said heating wire, said means bringing the heating wire in operative position or in inactive position are also controlling the electric current supply of the said heating wire.

3. A thread-cutting device according to claim 2, comprising an electro-plunger having an armature, a'small insulating plate secured tosaid armature, said heating wire being substantially U-shaped and being secured to said plate, a tubular element constituting an extension of said armature, said notched disc having a tubular. hub, said tubular element engaging said hub, said knitting machine having a machine'eylinder and an annular lid covering the head of the machine'cylin'der, andf'a-b'racket integral with said lid and carrying said tubular'elernent, said bracket also holding said electro-plunger.

4. A thread-cutting device according to'claim 3, wherein said armature of the electro-plunger has an annular shoulder limiting the downward stroke of said tubular element, the second-mentioned means comprising a microswitch carried by said bracket and controlling the electric current supply of the heating wire, said microswitch being actuated by said shoulder. l

5. A thread-cutting device according to claim 4, wherein the knitting machine has a programming device' and wherein the energizing of said electro-plunger is controlled from the programming device.

6. A thread-cutting device according to claim 4, comprising a cap having a truncated recess facing the underside of the notched disc, said cap being carried by said tubular element. 7

7. A device according to claim 2, comprising a tubular element supporting said heating wire and engaging a tubular hub of said notched disc, the upper portion of the said tubular element having a side finger, a helical spring permanently engaging said finger, a bracket supporting said notched disc, said spring leaning upon said bracket, a pivot carried by said bracket,'a lever linked to said pivot and temporarily engaging said side finger, the first-mentioned means comprising an electro-plunger supported by said bracket and connected with said lever.

References Cited UNITED STATES PATENTS 1,244,672 10/1917 Wilcomb 66145 XR 2,713,254 7/1955 Minton 66--145 3,030,788 4/1962 Peel 66140 3,079,779 3/1963 Butler et al. 66-140 3,174,307 3/1965 Mayer 66145 XR 3,224,230 12/1965 Dusik et al. 66145 FOREIGN PATENTS 685,501 4/1964 Canada.

WM. CARTER REYNOLDS, Primary Examiner. 

